Brake Bleeding

Bleeding patterns vary for different cars—consult the owner's manual and/or service manual for bleeding order as well as DOT-grade fluid recommendation and any ABS-specific procedures. Rear-wheel drive vehicles are bled beginning at the wheel that's farthest from the master cylinder, then gradually working in: typically right rear, then left rear, then right front and finally left front. Front-wheel drives are sometimes bled in a diagonal pattern.


For the actual 2-person blood-letting, The Pumper begins by slowly and steadily applying pressure to the brake pedal while The Dumper opens the bleeder. This forces fluid through the system. The Pumper alerts The Dumper to close the bleeder before the end of the pedal stroke to avoid damaging the master cylinder. The cycle continues until no more air bubbles are visible in the tubing and bottle. Remember to top off the master cylinder after every few pumps and dumps. Keep the lids on both the master and brake-fluid bottle to minimize sloshing and the opportunity for air to invade the fluid.


Once all air is bled, it makes sense to keep bleeding until fresh fluid emerges from the bleeder. When all wheels have been bled (and also the proportioning/combination valve in some vehicles), top off the master cylinder a final time, replace its lid and discard any remaining "new" brake fluid properly along with the old fluid—otherwise, moisture will accumulate inside the unsealed bottle during storage. Pump the pedal a few times to make sure that it's at least as firm—if not firmer—than in its pre-bleed state. Finally, road-test the brakes in an out-of-the-way place to verify they're functioning properly before driving in real-world conditions.

One-Person Methods
The automotive aftermarket includes a few products designed to make brake bleeding a 1-person operation. The three most common: vacuum pumps, pressure pumps and one-way bleeder screws.


Hand-operated vacuum pumps are the most popular for do-it-yourselfers. Affordable, these units suck fluid out through the bleeder, eliminating pedal pumping. However, air can be drawn in through the bleeders' threads if they don't seal tightly, giving the appearance of air in the system. Follow the instructions that come with the pump to learn its operation and the proper wheel-bleeding order for your car.